1. Field of Invention
This invention relates to modular tactile surfaces which are applied to roads, walkways and other areas of pedestrian traffic for providing guidance to persons who are visually handicapped. More specifically, the present invention relates to flexible tiles having circular and elongated tactile projections which alert the blind to hazardous conditions or provide travel directions.
2. Prior Art
Pedestrian delineation devices generally rely on visual recognition. For example, U.S. Pat No. 1,647,861 discloses a type of metallic button having a raised surface which provides guidance to pedestrians crossing a street. In most cases, these raised devices have been for the purpose of replacing painted crosswalk markings which tend to wear off. See, for example, U.S. Pat No. 1,698,594.
It is apparent that typical pedestrian delineation devices which depend on observation are unlikely to be useful to the visually handicapped person. It is estimated that 11,500,000 visually-impaired persons having impaired mobility exist within the United States. 500,000 of these individuals are legally blind. Some adaptations of pedestrian guidance devices have been oriented toward meeting the needs of such visually handicapped pedestrians. For example, U.S. Pat No. 4,080,087 describes a railess walkway which utilizes footplates which are fastened to the ground. These plates include humps which provide tactile guidance and orientation to the blind pedestrian. These footplates are designed to have a step region which enables the blind person to correctly position his foot on the footplate. Once in position, this footplate gives guidance as to the proper direction for movement. The footplate may further include a hump disposed within the step region to provide further information such as identification of hazards, obstacles, change in level or the like. Operation of this footplate depends upon proper orientation of the foot of the blind individual in the step region.
The narrow applications of the tile of the '087 patent fail to provide solutions to a major problem which has developed with the federal requirement for curb cuts and blended corners at crosswalks and curbs. The federal standard now requires that certain curbs include a curb cut which enables wheelchair pedestrians easy passage. Although only 645,000 physically handicapped persons fall within this need, this requirement has become a hazard for eleven and a half million visually impaired persons.
Such curb cut construction has resulted in at least seven (7) major problem areas. For example, curb cuts provide little tactile reference to indicate where the sidewalk ends and the street begins. A blind person may take one or more steps into the street without even being aware of the impending danger. More often than not, curb cuts are made an an angle to the street and tend to cause the blind individual confusion as to which direction he should take to cross to a safe corner. Similarly, curb cuts are typically not made within the crosswalk stripes themselves. Usually, they bisect the corner of the curb in order to facilitate directional travel across either of two intersecting streets. Unfortunately, the blind cannot see this diagonal path and may thereby be lead into the open intersection.
Blended corners, or corners in which the street is gradually tapered upward to meet the level of the curb, present an even more serious hazard. Blind individuals have no way of gaining an orientation as to the direction of pedestrian traffic to cross a street. Similarly, loading platforms at rapid transit or public transportation sites leave little guidance for visually handicapped persons as to safe waiting locations or directions of travel.
Recognizing the possible risk of curb cuts to the blind population, the federal government required the use of brush strokes and flanking borders of grooved lines at curb cut location. It has now been found that such actions have provided no useful function of guidance to the visually handicapped. Brush strokes are not detectable through footwear and grooved lines fail to give the warning and guidance that are needed.
Some development of more generic tiles for visually handicapped persons has occurred in Japan. Specific tiles having either raised dots or bars have been utilized to alert blind persons of special conditions. These tiles are 300 milimeters square and have a symmetrical array of either (i) round, truncated, hemispherical bumps or dots approximately 5 milimeters in height and 23 milimeters wide at the base and 11.5 milimeters at the top thereof or (ii) elongated bumps or bars. The latter bar tile includes four (4) elongated bumps disposed in parallel relationship across the surface of the tile. The length of these bars is approximately 285 milimeters and the width is approximately 34 milimeters at the base. These bars likewise taper to a top flat surface having a width of 22 milimeters. The bars and bumps are detected by use of the blind person's cue or cane. The nature of bump (circular or elongated) gives the blind person an instruction or appropriate direction. Although this design provides limited safety required for normal applications, some improvements are needed.
For example, the use of such tiles adherred to a sidewalk or road surface, fails to provide an optimum level of tactile sensitivity. An abrupt edge or tile corner can also pose a hazard to visually handicapped persons who have difficulty distinguishing sharp edges and changes in elevation. Such a corner may cause any pedestrian to stumble or trip and severely injure themselves.
Despite the variety of tactile devices which have been developed for assisting the visually handicapped, difficulty in developing an acceptable tile has continued. The problem creating this difficulty may be generally characterized at opposing sides of an apparent paradox for tile design. For example, a primary design guideline is to create a contoured surface which can be detected through the sole of the foot or with a cane to provide warning or directional information for the blind person. The ability to define specific tactile features which permit uniform recognition through the sole of a shoe has remained an unsolved problem. At the opposite side of the paradox is the need to maintain a low profile on any raised tile structure so that the physically handicapped and other pedestrians are not confronted with obstacles which may trip or otherwise cause injury to the pedestrians. In short, the design paradox for tactile plates or tiles for assisting visually handicapped is to create a contoured surface high enough to be detectable yet low enough not to create problems for both the physically handicapped and the unimpaired pedestrian.